PC Engine CDrom2 problems and fixes

[NeWmAn]

Recently I got an old PCE + Cd interface and CDRom unit, the CDRom had a few problems and here I'm describing the solutions I found.

1) CdRom2 Dead

Apparently the unit was dead, no signs of life, no led display and nothing happened when one of the buttons was pressed. The lens assembly was at the farthest point from the inner spindle.

Solution: I disassembled the unit and gently moved the lens assembly closer to the spindle until it reached the micro-switch, after re-assembly it worked! 
Note: I haven't been able to replicate the problem, even if I move (by hand) the lens assembly to an extreme point the unit works each time   .

2) Missing left channel from the headphone socket (Audio was OK on the line-out socket)

Solution: Corroded and interrupted track on the PCB ( it was hidden under the volume wheel  ), after bridging the gap the problem was fixed.

3) Track skipping
An audio track would play fine for a while and then skip to the next. During a game there would be either the wrong audio track or no sync between the action and the audio.

Solution:
There was dirt/grease in the helical screw that moves the head assembly so I removed and cleaned this part:

after re-assembly it worked flawlessly.

CD-R playback:
I've cleaned the lens with a simple q-tip

I've also cleaned the mirror under the lens coil assembly (!!!caution it's a delicate part!!!)

after this it seems to play CD-Rs  (quality media burnt at 8x) without a problem. I haven't had to adjust the diode power to compensate for the lower reflection.